Variable FindVariable(string name, bool lookInCurrentScopeOnly)
{
Contract.Requires(name != null);
VarContextNode c = varContext;
bool lookOnlyForConstants = false;
do
{
c.VarSymbols.TryGetValue(name, out Variable var);
if (var != null && (!lookOnlyForConstants || var is Constant))
{
return(var);
}
// not at this level
if (c.Opaque)
{
// from here on, only constants can be looked up
lookOnlyForConstants = true;
}
if (lookInCurrentScopeOnly)
{
// we're asked to look only in the current scope; hence, we're done
break;
}
c = c.ParentContext;
} while (c != null);
// not present in the relevant levels
return(null);
}
Variable FindVariable(string name, bool ignoreTopLevelVars)
{
Contract.Requires(name != null);
VarContextNode c = varContext;
bool lookOnlyForConstants = false;
do
{
if (ignoreTopLevelVars && c.ParentContext == null)
{
// this is the top level and we're asked to ignore the top level; hence, we're done
break;
}
Variable var = (Variable)c.VarSymbols[name];
if (var != null && (!lookOnlyForConstants || var is Constant))
{
return(var);
}
// not at this level
if (c.Opaque)
{
// from here on, only constants can be looked up
lookOnlyForConstants = true;
}
c = c.ParentContext;
} while (c != null);
// not present in the relevant levels
return(null);
}
/// <summary>
/// Requires there to be more than one variable context.
/// </summary>
public void PopVarContext()
{
Contract.Assert(varContext.ParentContext != null);
varContext = varContext.ParentContext;
}
/// <summary>
/// Adds an opaque variable context, that is, one that blocks all previously pushed contexts.
/// </summary>
public void PushOpaqueVarContext()
{
varContext = new VarContextNode(varContext, true);
}
/// <summary>
/// Adds a variable context.
/// </summary>
public void PushVarContext()
{
varContext = new VarContextNode(varContext, false);
}
public VarContextNode(/*maybe null*/ VarContextNode parentContext, bool opaque)
{
ParentContext = parentContext;
Opaque = opaque;
}
public VarContextNode(/*maybe null*/ VarContextNode parentContext, bool opaque)
{
ParentContext = parentContext;
Opaque = opaque;
}
/// <summary>
/// Adds a variable context.
/// </summary>
public void PushVarContext()
{
varContext = new VarContextNode(varContext, false);
}
/// <summary>
/// Adds an opaque variable context, that is, one that blocks all previously pushed contexts.
/// </summary>
public void PushOpaqueVarContext()
{
varContext = new VarContextNode(varContext, true);
}
/// <summary>
/// Requires there to be more than one variable context.
/// </summary>
public void PopVarContext()
{
Contract.Assert(varContext.ParentContext != null);
varContext = varContext.ParentContext;
}